Well then, the replacement blade on your plastic lawnmower sounds like a great option for a 3D printer, if you have one and don’t mind spending on the material. But I see the flymo site sells replacement blades for a mere £4, direct from the manufacturer. Can you beat that price with your printer? I doubt it.
But no one thinks 3D printing won’t happen – obviously it’s been happening for quite some time now. The problem is really for home manufacturing, which for most non-toy applications requires a) high quality materials, b) precise tolerances, and c) assembly of complex parts, none of which are available from cheap 3D printers. There are clearly some applications for which soft, brittle, or crudely rendered parts are just fine even today, but it’s not exactly going to be a near-term revolution, because most useful objects can’t be made with these machines.
